Neuroscience of Consciousness最新文献

Dissociations in types of memory tasks emerge when comparing feeling-of-knowing (FOK) judgments, predictions of upcoming performance, and retrospective confidence. This pattern has been used to construct theories of metacognitive access to memory, particularly in memory-impaired groups. In particular, older adults' metacognitive sensitivity appears to vary between episodic (impaired) and semantic (intact) memory. However, this could be explained by the limitations of metacognitive measures and/or memory differences. We aimed to test these dissociations of metacognition with aging by comparing metacognitive efficiency in episodic and semantic tasks using two types of judgment: retrospective confidence judgments (RCJs) and FOK judgments. Metacognitive efficiency was estimated in 240 participants aged 19-79 years using a hierarchical Bayesian framework. Results showed that metacognitive efficiency for RCJs declined with age in the semantic task, even though task performance increased with age, while metacognitive efficiency was stable in the episodic task. Surprisingly, metacognitive efficiency was very low (although significantly higher than zero) for both FOK tasks regardless of age compared to similar previous studies. We suggested this might be due to the online testing. These results point to metacognition being multifaceted and varying according to judgment, domains, and populations.

How is it that psychedelics so profoundly impact brain and mind? According to the model of "Relaxed Beliefs Under Psychedelics" (REBUS), 5-HT2a agonism is thought to help relax prior expectations, thus making room for new perspectives and patterns. Here, we introduce an alternative (but largely compatible) perspective, proposing that REBUS effects may primarily correspond to a particular (but potentially pivotal) regime of very high levels of 5-HT2a receptor agonism. Depending on both a variety of contextual factors and the specific neural systems being considered, we suggest opposite effects may also occur in which synchronous neural activity becomes more powerful, with accompanying "Strengthened Beliefs Under Psychedelics" (SEBUS) effects. Such SEBUS effects are consistent with the enhanced meaning-making observed in psychedelic therapy (e.g. psychological insight and the noetic quality of mystical experiences), with the imposition of prior expectations on perception (e.g. hallucinations and pareidolia), and with the delusional thinking that sometimes occurs during psychedelic experiences (e.g. apophenia, paranoia, engendering of inaccurate interpretations of events, and potentially false memories). With "Altered Beliefs Under Psychedelics" (ALBUS), we propose that the manifestation of SEBUS vs. REBUS effects may vary across the dose-response curve of 5-HT2a signaling. While we explore a diverse range of sometimes complex models, our basic idea is fundamentally simple: psychedelic experiences can be understood as kinds of waking dream states of varying degrees of lucidity, with similar underlying mechanisms. We further demonstrate the utility of ALBUS by providing neurophenomenological models of psychedelics focusing on mechanisms of conscious perceptual synthesis, dreaming, and episodic memory and mental simulation.

Consciously perceived emotional relative to neutral facial expressions evoke stronger early and late event-related potential (ERP) components. However, the extent of nonconscious neural processing of emotional information in faces is still a matter of debate. One possible reason for conflicting findings might relate to threshold effects depending on the sensory strength of stimuli. In the current study, we investigated this issue by manipulating the contrast of fearful and neutral faces presented with or without continuous flash suppression (CFS). Low, medium, and high contrasts were calibrated individually so that faces were consciously perceived at all contrast levels if presented without CFS. With CFS, however, low- and medium-contrast faces remained nonconscious, while high-contrast faces broke the suppression. Without CFS, ERPs showed an increased early negativity and late positivity in response to fearful vs. neutral faces regardless of contrast. Under CFS, we observed differential early negativities for suppression-breaking high-contrast fearful vs. neutral faces. For nonconscious faces, however, the contrast level modulated the difference between fearful and neutral faces, showing enhanced early negativities only at medium contrast and an inverted effect at low contrast. Additional analysis of late positivities provided evidence for the absence of an effect at low and medium contrast, while at high-contrast, fearful faces elicited a larger positivity than neutral ones. Taken together, our findings demonstrate the significance of stimulus strength for nonconscious emotion processing under CFS, implying that early negative ERP differences between neutral and fearful faces depend on stimulus contrast near the detection threshold.

This paper explores the relationship between intuition and flow from a neurodynamics perspective. Flow and intuition represent two cognitive phenomena rooted in nonconscious information processing; however, there are clear differences in both their phenomenal characteristics and, more broadly, their contribution to action and cognition. We propose, extrapolating from dual processing theory, that intuition serves as a rapid, nonconscious decision-making process, while flow facilitates this process in action, achieving optimal cognitive control and performance without [conscious] deliberation. By exploring these points of convergence between flow and intuition, we also attempt to reconcile the apparent paradox of the presence of enhanced intuition in flow, which is also a state of heightened cognitive control. To do so, we utilize a revised dual-processing framework, which allows us to productively align and differentiate flow and intuition (including intuition in flow). Furthermore, we draw on recent work examining flow from an active inference perspective. Our account not only heightens understanding of human cognition and consciousness, but also raises new questions for future research, aiming to deepen our comprehension of how flow and intuition can be harnessed to elevate human performance and wellbeing.

We apply the methodology of no-go theorems as developed in physics to the question of artificial consciousness. The result is a no-go theorem which shows that under a general assumption, called dynamical relevance, Artificial Intelligence (AI) systems that run on contemporary computer chips cannot be conscious. Consciousness is dynamically relevant, simply put, if, according to a theory of consciousness, it is relevant for the temporal evolution of a system's states. The no-go theorem rests on facts about semiconductor development: that AI systems run on central processing units, graphics processing units, tensor processing units, or other processors which have been designed and verified to adhere to computational dynamics that systematically preclude or suppress deviations. Whether our result resolves the question of AI consciousness on contemporary processors depends on the truth of the theorem's main assumption, dynamical relevance, which this paper does not establish.

This paper explores the limitations of neurobiological approaches to human emotional experience, focusing on the case of grief. We propose that grief is neither an episodic emotion nor a longer-term mood but instead a heterogeneous, temporally extended process. A grief process can incorporate all manner of experiences, thoughts, and activities, most or all of which are not grief-specific. Furthermore, its course over time is shaped in various different ways by interpersonal, social, and cultural environments. This poses methodological challenges for any attempt to relate grief to the brain. Grief also illustrates wider limitations of approaches that conceive of emotions as brief episodes, abstracted from the dynamic, holistic, longer-term organization of human emotional life.

Despite the dramatic rise of surveillance in our societies, only limited research has examined its effects on humans. While most research has focused on voluntary behaviour, no study has examined the effects of surveillance on more fundamental and automatic aspects of human perceptual awareness and cognition. Here, we show that being watched on CCTV markedly impacts a hardwired and involuntary function of human sensory perception-the ability to consciously detect faces. Using the method of continuous flash suppression (CFS), we show that when people are surveilled (N = 24), they are quicker than controls (N = 30) to detect faces. An independent control experiment (N = 42) ruled out an explanation based on demand characteristics and social desirability biases. These findings show that being watched impacts not only consciously controlled behaviours but also unconscious, involuntary visual processing. Our results have implications concerning the impacts of surveillance on basic human cognition as well as public mental health.

Auto-induced cognitive trance (AICT) is a modified state of consciousness derived from shamanic tradition that can be practised by individuals after specific training. The aim of this work was to characterize the phenomenological experiences of AICT, using text mining analysis. Free recalls of subjective experiences were audio-recorded in 27 participants after five pseudo-randomized experimental sessions: ordinary conscious resting state, with auditory stimulation and with an imaginary mental task, as well as during AICT with and without auditory stimulation. Recordings were transcribed, normalized total word counts were calculated for each condition, and analyses of content were performed using IRaMuTeQ software. Results showed that the length of the participants' reports was higher for AICT compared to the other conditions, and that the content could be categorized into four classes of discourse: AICT memory, AICT, ordinary conscious states, and AICT with and without stimulation. AICT was also characterized by specific content compared to rest, auditory stimulation, and imagination conditions. Content analysis of the narrative revealed nine categories encompassing the presence of nature, people, animals, positive and negative features, sensory perceptions, body modifications, metacognition, and difficulty of describing thoughts. Among these categories, AICT is specifically characterized by reports related to the presence of nature, animals, body modifications, as well as the difficulty of describing thoughts. These results suggest that a richer phenomenology was reported during AICT, compared to the other conditions, and that AICT constitutes a class of discourse on its own, with a clear dissociation from the other conditions.

The question of the richness (or sparseness) of conscious experience has evoked ongoing debate and discussion. Claims for both richness and sparseness are supported by empirical data, yet they are often indirect, and alternative explanations have been put forward. Recently, it has been suggested that current experimental methods limit participants' responses, thereby preventing researchers from assessing the actual richness of perception. Instead, free verbal reports were presented as a possible way to overcome this limitation. As part of this approach, a novel paradigm of freely reported words was developed using a new metric, intersubjective agreement (IA), with experimental results interpreted as capturing aspects of conscious perception. Here, we challenge the validity of freely reported words as a tool for studying the richness of conscious experience. We base our claims on two studies (each composed of three experiments), where we manipulated the richness of percepts and tested whether IA changed accordingly. Five additional control experiments were conducted to validate the experimental logic and examine alternative explanations. Our results suggest otherwise, presenting four challenges to the free verbal report paradigm: first, impoverished stimuli did not evoke lower IA scores. Second, the IA score was correlated with word frequency in English. Third, the original positive relationship between IA scores and rated confidence was not found in any of the six experiments. Fourth, a high rate of nonexisting words was found, some of which described items that matched the gist of the scene but did not appear in the image. We conclude that a metric based on freely reported words might be better explained by vocabulary conventions and gist-based reports than by capturing the richness of perception.

Internal feeling states such as pain, hunger, and thirst are widely assumed to be drivers of behaviours essential for homeostasis and animal survival. Call this the 'causal assumption'. It is becoming increasingly apparent that the causal assumption is incompatible with the standard view of motor action in neuroscience. While there is a well-known explanatory gap between neural activity and feelings, there is also a disjuncture in the reverse direction-what role, if any, do feelings play in animals if not to cause behaviour? To deny that feelings cause behaviours might thus seem to presage epiphenomenalism-the idea that subjective experiences, including feelings, are inert, emergent and, on some views, non-physical properties of brain processes. Since epiphenomenalism is antagonistic to fundamental commitments of evolutionary biology, the view developed here challenges the standard view about the function of feelings without denying that feelings have a function. Instead, we introduce the 'sense making sense' hypothesis-the idea that the function of subjective experience is not to cause behaviour, but to explain, in a restricted but still useful sense of 'explanation'. A plausible framework is derived that integrates commonly accepted neural computations to blend motor control, feelings, and explanatory processes to make sense of the way feelings are integrated into our sense of how and why we do and what we do.